Elongated switch having spaced rib actuating means



United States Patent Inventors Walter A. Wolf;

Prentice R. Corn, Logansport, Indiana 828,641

May 28, 1969 Dec. 1, 1970 Switches, Incorporated a corporation of Indiana Appl. No. Filed Patented Assignee ELONGATED SWITCH HAVING SPACED RIB ACTUATING MEANS 5 Claims, 4 Drawing Figs.

U.S. C1 200/86, ZOO/61.57

Int. Cl. H01h 3/14 Field of Search 200/86, 85,

[56] References Cited UNITED STATES PATENTS 2,213,409 9/1940 Quilliam 200/86(UX) 3,118,984 1/1964 Koenig ZOO/86X 3,476,897 11/1969 Vincent.... ZOO/61.57 3,485,974 12/1969 Wolf et a1. ZOO/61.57

Primary Examiner-Robert K. Schaefer Assistant Examiner-D. Smith, Jr. Attorney-Dressler, Goldsmith, Clement & Gordon ABSTRACT: This invention relates to an electrical switch which includes a pair of resilient metal contact strips mounted in parallel spaced relationship in a hollow resilient primary casing to form a switch element and a cover member in the form of a resilient shell adapted internally with spaced rib element for engagement with said switch element or said primary casing to actuate the switch.

ELONGATED SWITCH HAVING SPACED RIB ACTUATING MEANS This invention relates to electrical switches. More particularly, it relates to switches of the type having ribbonlike metal strips for momentary contact electrical switching extending longitudinally in a casing. Still more particularly, it relates to an assembly having a casing with a hollow central passage and spaced contact strips mounted therein, said casing having a resilient decorative and functional cover for the switch permitting hiding the switch from view while retaining its response to finger pressure.

Briefly, the electrical switch of this invention comprises a pair of resilient metal contact strips mounted in spaced relationship in a hollow resilient primary casing and a cover member adapted internally with spaced fin or rib elements, a portion of which rib element may engage the upper metal contact strip or a portion of the primary casing overlaying said upper metal contact strip.

Switching mechanisms intended for use in electrical circuit under emergency conditions require ready availability and rapid response. For example, the modern automobile restyled for improved safety as by eliminating protrusions. etc., create the problem for the driver to locate instantly buttons that are positioned flush with surrounding deck, or the so-called hidden horn rings set in recesses. Another safety requirement, that of crash padding has restricted the positions where switching can be located.

Strip or ribbon switches which comprise two relatively thin, flexible, electrically conductive metallic strips held in spaced, out of contact relationship by peripheral insulating members can be produced in varying lengths and widths to give a relatively large surface area for contact by the hands of the vehicle driver. However, overlaying such switches with safety pad coverings presents problems of increased pressure requirements, maintaining uniformity in touch response with a minimum of deflection and minimizing variations in touch response due to effect of temperature changes on resilient materials.

Now it has been discovered that a new and novel construction of a momentary contact type strip switch permits matching of style and material to the surroundings, for example, the crash pad interior of an automobile, while retaining the soft feel and ready response to finger pressures, by the use of (l) a primary casing which is securable to a support base, said casing having an elongated passage extending longitudinally of said casing, (2) a pair of elongated resilient metal contact strips mounted in the elongated passage in said casing in spaced normally electrically insulated positions to form an inner switch structure, said elongated metal strips upon deflection over any portion of their length, being engageable with each other to complete an electrical circuit, and (3) a resilient flexible shell member forming a cover with sides and crown portions spaced from the periphery of said primary casing at the top and sides, a plurality of spaced fin members being positioned interiorly of said shell and extending through the crown portion thereof, said fin members having a dimension from said shell to the inner terminal edges of said fins providing for edgewise engagement with at least portions of the exterior of said inner switch structure, said engaging fins in said crown portion of said shell due to structure and spacing simultaneously transmitting an actuating force and absorbing a portion of said force thereby providing additional travel by collapsing for cushion effect while creating deflection of said metal strips. In a preferred form of this invention, said fin elements have longitudinal axes extending transverse to the longitudinal axis of said primary casing.

The primary casing and the shell member both may be fonned of nonconducting resilient material. The primary casing and shell member may consist of the same or different materials. Suitable resilient materials are natural rubber, synthetic elastomers such as polymerized butadiene and styrene, vinyl resins, and the like. Both the primary casing and shell member may be formed by a continuous extrusion process, molding or a combing combination of both.

The shell member, if the switch is to be mounted, for example, on the spokes of an automobile steering wheel may have a uniform or nonuniform thickness exterior skin, generally uniform, and of about 1/32 to /5 inch thickness. The size of the shell member will depend upon the size, i.e., width and height, of the primary base to be enclosed and the spacing desired between the base and the skin of the shell member.

The soft feel and ready response to finger pressures is subject to control based primarily on three factors, namely, the natural stiffness characteristic of the resilient material of construction of the shell member, the thickness of the shell and structure of the fins within the shell.

Feel ofthis shell member is determined by the number of internal fin elements and their width and height as well as their spacing. Spacings vary from about a gap equal to the fin width to about twice the fin width. The height of the fins depends upon the positioning of the shell relative to the actuating axis of the switch. Generally, if the primary casing entirely encloses the strip member, i.e., has an outer longitudinal flexible portion depressible into the cored central passage in the easing to flex the metal strips into contact, the fins within the shell member have a height over the crown portion of said shell such that the interior edge of the fins make contact with the top of the longitudinal flexible portion of the primary casing. The configuration of the interior edges of the fins of the crown area may match the outer configuration of the resilient con tact portion of the primary casing or may be planar in configuration so as to make contact merely over a limited area. If the primary casing has spaced lips which leave part of the upper metallic strip exposed, the fins may be formed with an interior edge configuration matching the top periphery of the enclosed unit and of a height at the lateral portions of the crown section to contact the lips of the primary casing and of a height between the lateral portions to make direct contact with the upper metallic strip. The fin portions on opposite sides of the crown portion of the shell extend downward along the sides of the primary casing a distance approximately equal to the height of the lateral sides of the primary casing and have an interior edge configuration matching the sides of the primary casing so as to provide a close fit and to secure the shell against lateral movement.

The advantages of such a construction are to provide a relatively long surface for a switch which is readily locatable by a drivers hand, even under conditions inducing tensing up, and still give the protection of a yielding surface which will absorb pressure to afford the driver increased safety against injury.

The capabilities of the invention will be apparent to those skilled in the art from the following description of preferred embodiments thereof taken in conjunction with the accompanying drawings in which:

FIG. I is a perspective view of a complete assembly, with part of the shell broken away to show the primary casing and with part of the primary casing broken away to show the metallic strip elements;

FIG. 2 is a sectional view along'the line 2-2 of FIG. I;

FIG. 3 is a bottom plan view along the line 3-3 of FIG. 2; and

FIG. 4 is a sectional view of an embodiment where the internal fins of the shell member make direct contact with the electrically conductive strips mounted in a primary casing having an open area at the top thereof.

As shown in FIGS. 1, 2 and 3, the switch member 10 is made up of a pair of metallic contact strips 11 and 12 mounted in the cored portion 13 of a resilient tubularlike casing member 14 secured to a base 15 by latch lips 14 a which are releasable held in place by overlapping lipslS a ofthe base 15. The tubular casing member 14 has planar vertical sides 16 and 17 and a convex curvature upper portion 18.

Contact strips 11 and 12 are illustrated as having embossed protuberances, i.e., transverse protuberances on strip 11 and a longitudinal protuberance on strip 12 which are engageable at a plurality of space spaced contact points when strip I2 is deflected from the normal position. It will be understood that the configuration of the base may be such that either metallic strip may be deflected. Contact strips, usable in the casing member, may be made of a resilient metal such as copper, copper alloy, beryllium-copper etc., with planar or other suitable surface configuration.

Extending from the sides of cored portion 13 of primary casing member 14 are pairs of slot members 19 and 20 which are continuous over the length of the casing. Slot members 19 provide a support means for lower contact strip 11 and slot members 20 provide a support means for the upper contact strip 12.

The base 15 to which primary casing 14 is secured may be of any suitable configuration depending upon the support unit to which it is to be secured. The front face or upper portion 18 of casing 14, as illustrated in FIGS. 1, 2 and 3, is formed to provide an actuating surface which requires some degree of pressure before being sufficiently depressed to bring strips 11 and 12 into contact.

' Enclosing said primary casing 14 and the base 15 is resilient shell member 22. Shell member 22 on its upper exterior surfaces may have any suitable external configuration. The shell member may be provided with suitable lips 23 and 24 adapted to cooperate with shaped base 15 to hold it and shell member 22 in engagement. Shell member 22 is provided internally with ribs 25 also of resilient material. Ribs 25 may have any'suitable configuration at their free ends'to make contact with said primary casing 14. As illustrated, rib 25 is provided with a triangular portion 26, the flat base of which is in contact with upper portion 18 of primary casing 14. Ribs 25 are provided with downwardly extending projections 27 and 28 which have a planar inner surfaces in contact with the planar vertical sides 16 and 17, respectively, of primary casing 14.

Referring to to FIG. 4, the switch member 30 is of a type having a primary casing 31 with vertical sides 32 and 33 which are adapted with strip securing lips 34 and 35, respectively. The terminal surfaces 36 and 37, respectively, of lips 34 and are spaced so that top metallic strip 38 has the top surface thereof in an exposed position. primary casing 31 is secured, in a manner similar to that used to secure casing 14 to base 15, to a base 39.

As in FIG. 1, a shell member 40 substantially encloses said primary casing 31 and base 39. Shell member 40 is provided with suitable lips 41 and 42 to engage the bottom of base 39 to hold it and shell member 40 in engagement.

Shell member 40 is provided internally with ribs 43. Ribs 43 are provided with a portion 44 in the crown thereof, the flat bottom edge of which engages metallic strip 38. Ribs 43 also have downwardly extending projections 45 and 46 which have planar inner edges in contact with vertical sides 32 and 33 of primary casing 31.

'orly Such switch members may be secured to a support base by adhesives or as by fitting into a suitably shaped recess, with or without the aid of adhesives.

The particular arrangement of installing the switching means on a suitable base and of connecting it to suitable electrical conductor systems, depends, of course, on the particular base structure encountered. While one form of connecting the switch to the electrical circuitry is shown herein, the use of other connecting means is contemplated within the scope of this invention. i

We claim:

1. An electrical switch comprising a primary casing having an elongated passage extending longitudinally of said casing, a pair of elongated resilient metal contact strips mounted in the elongated passage in said casing in spaced normally electrically insulatedpositions forming an inner switch structure, said elongated metal strips upon deflection over any limited portion of their length, being engageable with each other to complete an electrical circuit, a resilient flexible shell member forming a cover with sides and crown portions spaced from the periphery of said primary casing at the top and sides thereof, a plurality of spaced fin members positioned interiof said shell and extending through the crown portion thereof, said fin members having a dimension from said shell to the inner terminal edges of said fins providing for edgewise engagement with at least portions of the exterior of said inner switch structure, said engaging fins in said crown portion of said shell simultaneously transmitting an actuating force in a direction such as to create deflection of said metal strips and providing additional travel by collapsing for cushion effect.

2. An electrical switch according to claim 1 wherein said elongated passage in said primary casing is formed as a cored central passage in said casing and said casing has an integrally formed flexible portion depressible into said elongated passage and said fins in said crown portion of said shell engage' said depressiblc flexible portion of said primary casing.

3. An electrical switch according to claim 1 wherein said primary casing is provided with spaced lips for holding the upper one of said metallic strips in position and said fins in said crown portion of said shell directly engage the portion of said upper metallic strip exposed between said lips.

4. An electrical switch according to claim 1 wherein said fins are formed as an integral part of said shell member.

5. An electrical switch according to claim 1 wherein said fin members have the longitudinal axis thereof extending transverse to the longitudinal axis of said primary casing. 

